Constraints on Sub-GeV Dark Matter–Electron Scattering from the CDEX-10 Experiment
Z. Y. Zhang, L. T. Yang, Q. Yue, K. Kang, Y. J. Li, M. Ağartıoğlu, Haipeng An, Jianping Chang, Y. H. Chen, J. Cheng, W. H. Dai, Z. Deng, C. H. Fang, X. P. Geng, Haipeng Gong, Q. Guo, Xiangbo Guo, Long He, S. M. He, J. W. Hu, Han‐Xiong Huang, T. Huang, Hai-Tao Jia, Xi Jiang, H. B. Li, J. M. Li, J. Li, Q. Y. Li, R. M. J. Li, X. Q. Li, Y. L. Li, Y. F. Liang, Bin Liao, F. K. Lin, S. T. Lin, S. K. Liu, Y. D. Liu, Y. Liu, Y. Y. Liu, Z. Z. Liu, Hao Ma, Yajun Mao, Q. Y. Nie, J. H. Ning, H. Pan, Ningchun Qi, J. Ren, Xichao Ruan, Kapil Saraswat, V. Sharma, Z. She, M. K. Singh, Tao Sun, C. J. Tang, W. Y. Tang, Y. Tian, G. F. Wang, Lingling Wang, Qing Wang, Y. Wang, Yanru Wang, H. T. Wong, Yongcheng Wu, Y. C. Wu, Haoyang Xing, R. Xu, Y. Xu, Tao Xue, Yulu Yan, Chih-Hsiang Yeh, Yi Nan, C. X. Yu, H. J. Yu, J. F. Yue, M. Zeng, Zhi Zeng, B. T. Zhang, F. S. Zhang, L. Zhang, Z. H. Zhang, K. K. Zhao, M. G. Zhao, Jifang Zhou, Z. Y. Zhou, J. J. Zhu
Abstract
We present improved germanium-based constraints on sub-GeV dark matter via dark matter--electron ($\ensuremath{\chi}\text{\ensuremath{-}}e$) scattering using the $205.4\text{ }\text{ }\mathrm{kg}\ifmmode\cdot\else\textperiodcentered\fi{}\mathrm{day}$ dataset from the CDEX-10 experiment. Using a novel calculation technique, we attain predicted $\ensuremath{\chi}\text{\ensuremath{-}}e$ scattering spectra observable in high-purity germanium detectors. In the heavy mediator scenario, our results achieve 3 orders of magnitude of improvement for ${m}_{\ensuremath{\chi}}$ larger than $80\text{ }\text{ }\mathrm{MeV}/{\mathrm{c}}^{2}$ compared to previous germanium-based $\ensuremath{\chi}\text{\ensuremath{-}}e$ results. We also present the most stringent $\ensuremath{\chi}\text{\ensuremath{-}}e$ cross-section limit to date among experiments using solid-state detectors for ${m}_{\ensuremath{\chi}}$ larger than $90\text{ }\text{ }\mathrm{MeV}/{\mathrm{c}}^{2}$ with heavy mediators and ${m}_{\ensuremath{\chi}}$ larger than $100\text{ }\text{ }\mathrm{MeV}/{\mathrm{c}}^{2}$ with electric dipole coupling. The result proves the feasibility and demonstrates the vast potential of a new $\ensuremath{\chi}\text{\ensuremath{-}}e$ detection method with high-purity germanium detectors in ultralow radioactive background.